Formation of New Zealand Pounamu- Nephrite Jade
Jade, Pounamu, Greenstone and Nephrite are all names associated with a precious gemstone found only on the West coast of the South Island of New Zealand. The Maori word Pounamu is also used to describe other precious stones like serpentine and bowentine. NZ Jade was and still is a revered taonga (treasure) to Maori and was used to make tools, weapons, adornment and gifts.
How is Jade formed?
Jade is formed in subduction zones which, are collisions between two tectonic plates. The plates involved in the creation of our Pounamu are the Pacific and Australian plates. The Pacific plate which carries the chemicals necessary for the formation of Jade flows under the Australian plate. This collision combined with high pressure and relatively low temperatures create the structure of our Pounamu.
Chemical Properties
Nephrite consists of interlocking fibres of calcium, magnesium iron rich amphibole. The higher the iron content, the greener the colour. Nephrite Jade is a tough stone graded at 6.0-6.5 on the Mohs scale, with diamond as a 10.